Cyclin-dependent kinase 4 and 6 are two enzymes that help tumor cells grow. Palbociclib works by blocking the action of CDK 4 and 6 that signals cancer cells to multiply. This helps slow the growth or spread of cancer cells.
Palbociclib is a pill. It is usually taken with food once a day, at the same time each day, for the first 21 days of a 28-day cycle. You and your doctor will discuss how many times you should repeat this cycle.
The most common side effects of palbociclib are:
- neutropenia, a low white blood cell count that makes infection more likely
- low red blood cell count, which can lead to fatigue
- low blood platelet count, which can cause abnormal bleeding
- nausea and vomiting
- small sores or ulcers in the mouth or on the lips
- hair loss
- low appetite
- nerve damage
Call your doctor immediately if you have any signs of infection, shortness of breath, chest pain, irregular heartbeat, weakness or unusual bleeding.
Before starting palbociclib, be sure to tell your doctor about any medicines you are taking, including vitamins, herbal supplements and over the counter medicines. Also tell your doctor if you have ever had liver or kidney disease. You should avoid grapefruit and grapefruit juice while you are taking this medicine.
You should avoid becoming pregnant while you are receiving palbociclib and for at least 2 weeks after taking the last dose. Tell your doctor right away if you become pregnant or may be pregnant while you are undergoing treatment.